1. Technical Field
The present invention relates to a detection circuit, a sensor device, an electronic apparatus, and the like.
2. Related Art
Infrared detection circuits in which pyroelectric elements or the like are employed are conventionally well-known. For example, infrared rays having wavelengths near 10 μm radiate from the human body, and detecting these rays allows information about the presence and temperature of a human body to be acquired without physical contact. Using such an infrared detection circuit therefore allows intrusion detection or measurements of physical quantities to be implemented.
The technology disclosed in the following publications is well-known for infrared detection circuits. In a non-patent publication, “Pyroelectric infrared sensors with fast response time and high sensitivity using epitaxial PbZr, TiO3 films on epitaxial γ-Al2O3/Si substrates” (Daisuke Akai et al., Sensors and Actuators A: Physical, Volumes 130-131, 14 Aug. 2006, Pages 111-115, Elsevier Science B. V.), a source follower circuit, which is configured from a transistor (JFET) and a resistor connected in series, is used to detect the pyroelectric current of a pyroelectric element.
In Japanese Laid-Open Patent Application No. 2009-68863, a P-type transistor that functions as a load element and an N-type transistor that functions as an amplifier element are connected in series, whereby a common-source amplifier circuit is configured, and this common-source amplifier circuit is used to detect the pyroelectric current of a pyroelectric element.